In this study a industrial survey was performed on the secondary products generated in the Dutch metal industry. From this industrial survey it was concluded that the Dutch metal industry is already far ahead with closing the materials cycle as for almost every product is a processing route to recover its metal content.
The residues generated at LDM BV, a secondary brass producer located in Drunen, are currently being processed by a different company; however in their goal to have a zero footprint on the environment LDM BV (hereafter referred to as LDM) is looking for opportunities to process the secondary products on site. Two different kinds of products are generated at LDM; a filter dust containing around 80% ZnO, 8% C, 4% Cu and 1.5% Pb and a slag containing various amounts of copper ~45% and zinc ~40% in metallic and oxide form.
A study was performed on the processing techniques available to process zinc containing residues and from this study several treatment options were designed and tested in the lab. The main focus was put on the recovery of zinc from the LDM filter dust as this is the first goal the company has set itself, however since the nature of the two materials is similar a combined treatment of both materials was investigated as well.
First the pyrometallurgical reduction by utilizing the carbon contained in the LDM filter dust was tested at 1200oC. It was found that a maximum of 97% of the zinc could be recovered; a higher recovery at 1200oC was not possible as the remaining zinc was bound to gahnite (ZnAl2O4). The residue still contained 15% ZnO and did not form a slag.
A combined reduction of both the filter dust and melting slag resulted in the recovery of 96.8% of the copper, 99.9% of the zinc (as ZnO) and 64.9% of the lead. This test was performed at 1400oC and it was found that at this temperature the gahnite would be reduced. Also by addition of lime and silica a suitable slag was formed which contained 2.18% CuO and 0.16% ZnO. Both the copper and zinc oxide produced had a purity of over 98%.
Hydrometallurgical treatment was tested by using two different leaching agents, NaOH and H2SO4. It was found that the best leaching conditions for NaOH at a liquid solid ratio of 10 were 90oC using 320 g/L NaOH. After 15 minutes the maximum amount of zinc was already leached and total of 86% was leached. Lead was leached for 68% and Copper for 5%.
Using 200 g/L H2SO4 at 65oC resulted in 96% of all the zinc to be leached and 90.5% of all the copper. Both residues contained mainly gahnite which is impossible to leach under atmospheric conditions.
After an iron removal step for the acidic solution both leach liquors were purified with Zn dust cementation. A zinc product of 99.7% purity was produced through electrowinning for both solutions; however the power consumption for the NaOH solution was significantly lower at 2.2 kWh/kg opposed to 3.04 kWh/kg zinc produced
Finally a conceptual flow sheet is given for both a pyrometallurgical and a (sulfuric acid) hydrometallurgical processing facility in a brass smelting plant.

Vanadium is an important industrial metal that is mostly used as an alloying element in steel and to a lesser extent in titanium. It is generally produced in combination with other metals such as iron, titanium, and uranium. The typical production method begins with salt roasting of the ore or concentrate to produce a water soluble form of vanadium. Then the vanadium is leached, purified and precipitated as vanadium pentoxide. Most of the vanadium pentoxide produced is then combined with iron to create a ferrovandium alloy, via aluminothermic reduction, that is suitable for the iron and steel industry for alloying.
Vanadium is also found in crude oil in a range that can vary from 10 to 1400ppm depending on the location. As the oil is processed and refined the vanadium becomes enriched. Specifically it is enriched in the fly ash of heavy fuel oil power plants. While the original concentration of vanadium in oil is very small the amount of oil extracted from the earth is very large and this makes fly ash a significant source of vanadium.
The vanadium that is contained in the heavy oil fly ash can be recovered by two general methods: hydrometallurgical and pyrometallurgical. The hydrometallurgical route usually involves leaching, purification, and precipitation to produce V2O5. This V2O5 can then be used to produce ferrovanadium.
The developmental pyrometallurgical route directly uses the fly ash in combination with a reductant (C, Al, or Si) and a source of iron to produce a ferrovanadium alloy. This thesis investigates one pyrometallurgical method, which uses two industrial waste products, heavy fuel oil fly ash and basic oxygen furnace dust, to produce a ferrovanadium alloy. The carbon contained within the fly ash is used as the reductant so only fluxing agents must be added to the charge. The result is a very efficient process that requires very few virgin raw materials.
The results show that a ferrovanadium alloy with 15% vanadium can be produced by high temperature smelting of heavy oil fly ash and basic oxygen furnace dust. There are some impurities that remain in the metal, mainly nickel (~4%), sulfur (~5%), and carbon (~1.5%). The carbon to metal ratio had the largest effect on the final metal quality. The slag quality is also important to the final quality but more work must be done in this area.
Simple water leaching tests were done on the as-received fly ash and the slag produced from smelting. The leach solution produced from the slag contained 100 times less metals than the solution produced from the as-received fly ash.

This report introduces a method for the removal of zinc from aircraft aluminium-alloy scrap. The driving force for this research is the demand from the secondary aluminium industry for a low zinc content in the Al-alloy scrap, and the growing demand for aluminium in the world. Meanwhile large amounts of obsolete aircraft are stored because of the problems during recycling of the aluminium.
The influence of coating on the aircraft scrap recycling is studied by treating the scrap in a de-coating process, regarding its influence on the melting process of the scrap. The coating accounts for approximately 1,6 wt% of the scrap. On a small scale, the melting of de-coated scrap shows much better results in coalescence and the separation of alloy from slag. On a larger scale, the melting results are also better for de-coated scrap, while the melting process of not de-coated scrap forms a reasonably coalescent alloy piece.
The recyclability of aircraft scrap is studied in the presence of different salt fluxes. The addition of 10 wt% cryolite promotes the coalescence of the alloy and the separation of alloy and slag. However, this salt flux removes magnesium from the alloy. Addition of magnesium fluoride maintains or even increases the magnesium content in the alloy, but gives poor results in the melting process. The use of a higher salts-to-alloy ratio does not improve the melting results and possibly even counteracts the evaporation of zinc for both cryolite and magnesium fluoride as an addition.
To improve the zinc removal from the aluminium alloy, a lance is used to blow argon gas into the alloy melt. The argon gas reduces the partial pressure of zinc, thereby promoting the evaporation of zinc from the melt. The tests are performed on an alloy with an initial zinc content of 2,42 %. A test with argon blowing lowers the zinc content to 1,88 %. However, a similar test without argon blowing results into an alloy with a zinc content of 2,11 %. The argon blowing only reduces the zinc content with 0,23 % compared to the similar test in which the same alloy is molten but no argon is blown into the melt.

Aerospace aluminium alloys (7xxx and 2xxx series Al alloy) is one of the important Al alloys in our life. The recycling of aerospace Al alloy plays a significant role in sustainable development of Al industry. The fibre reinforced metal laminates GLARE including 67 wt.% 2024 Al alloy was used as upper fuselage in Airbus A380, but the solution for GLARE recycling is not available. Thermal recycling which uses high temperature to decompose the resin and separate the reinforcement fibres and fillers, has been used in the thermal delamination of Lacomet (one member of fibre metal laminates family). Similar to the thermal recycling of Lacomet, a practical solution for GLARE recycling in laboratory-scale was developed in this research.The recycling of GLARE consists of two steps. The first step is the separation of S2-glass fibre and 2024 Al sheets after the decomposition of resins in GLARE under thermal condition, the decomposition behaviour as well as the decomposition kinetics of resins in GLARE were studied. The second step is the re-melting and refining of the separated 2024 Al sheets, the critical influence factors such as the salt flux composition, refining temperature, the size of 2024 Al scrap and the ratio of salt flux to scarp were discussed in this research.
Si is a harmful impurity for aerospace Al alloys, and Si concentration is strictly controlled in aerospace Al alloys. But a small amount of Al alloy scrap with high Si concentration is usually mixed together with aerospace Al alloy scrap during the recycling of aerospace Al alloys, thus Si concentration in final secondary aerospace alloys exceeds the upper limit of nominal concentration. Besides the improvement of the efficiency of scrap classification, the removal of impurity Si from recycled aerospace Al alloys is also an option to improve the quality of secondary aerospace Al alloys. In this research, the first attempt on Si removal from Al in laboratory-scale was conducted by using Ti addition method.

The blast furnace consumes a large amount of high quality metallurgy coke (size 35-80 mm) in addition to ore in the form of pellets and sinter. This coke is the coarse fraction, derived from the coke plant. The fine fraction (8 -35 mm), arise after sieving, named nut coke, can’t be directly used in blast furnace. The fraction of smaller than 8 mm is used in the sinter plant. Therefore, a large fraction of coke around 20 % from coking plant/process is not used for iron ore reduction. Recent research indicates that usage of nut coke will be economic if properly used. Nut coke cannot be directly mixed with normal coke because it will decrease the permeability of the coke layer in the blast furnace. However, mixing nut coke into the ferrous burden layer could be an effective way to use the coke resource economically. This mixed charging could improve softening and melting behaviour, reduction kinetics and permeability and also make full use of the coke resource. It may, however, also worsen the layer permeability and even deteriorate the whole blast furnace process. The mechanism of the effect of mixing nut coke into the ferrous burden on the performance of the blast furnace is still not clear, and thus the usage of nut coke is still limited.
To investigate the effect and mechanism of using nut coke in the ferrous burden on the performance of the blast furnace, cold flow model experiments and high temperature experiments have been conducted. An advanced Reduction, Softening and Melting experimental facility (RSM) was designed for high temperature experiments at TU Delft.

This thesis studies the zinc extraction from spinels through hydro and pyrometallurgical processing. Two zinc-bearing spinels are covered: zinc ferrite ZnO·Fe2O3 to a limited extent and gahnite ZnO·Al2O3 as the main subject, compounds which are found naturally on the Earth’s crust as well as in industrial residues from the zinc industry, steel industry and others. Zinc ferrite contains 27 % of Zn and 33 % as ZnO; resource recovery from ferrite has been studied already in the past. On the other hand, the processing of gahnite, containing 35 % of Zn and 44 % as ZnO, is studied more extensively since research in the field of extractive metallurgy is effectively non-existent. Hence, the main objective of the present thesis is finding routes of treatment for this spinel.
Zinc ferrite was produced synthetically at the CiTG/3mE labs by mixing equimolar amounts of ZnO and Fe2O3 at 1100 °C. Gahnite was produced by an analog method, a mixture of equimolar amounts of ZnO and Al2O3.
The first approach was hydrometallurgical. Atmospheric hot acid leaching (4 M, 95 °C, 120 min, L/S 40) was performed with H2SO4, HCl and HNO3, resulting in a non-detected dissolution of the compound. Pressure leaching (90 min, L/S 40) was carried out in an autoclave with H2SO4 and HNO3, resulting in a low (2.9 %; 0.75 M, 140 °C, 3.6 bar) and a moderate extraction (22.2 %; 4.0 M, 250 °C, 39.7 bar) respectively.
The second approach was pyrometallurgical processing (60 min dwell, 10 °C/min heating rate), divided into two sub-routes. A series of carbothermic tests (1:1.25 stoichiometric ratio) successfully led to a full reduction of the spinel at 1300 °C (99.90 % extraction of zinc). Aluminothermic tests (1.5:2 stoichiometric ratio) successfully resulted in a 99.98 % zinc extraction at 1200 °C.
The mix of gahnite and ferrite with carbon at 1300 °C produced a 99.65 % extraction of the metal. Addition of ZnO to the previous mixture resulted in a 100 % extraction, at 1300 °C. Further experiments with gahnite at 1200 °C by adding SiO2, first with carbon and later with aluminium, resulted in a moderate 23.14 % and a low 4.69 % extraction correspondingly. Trials with CaO at 1400 °C created a glass residue and a slag, in each case.
It is thus possible to establish the zinc extraction from gahnite ZnO·Al2O3 as follows:
Route / Zinc extraction
Atmospheric acidic leaching / Non-detected
Pressure leaching / Low – Moderate
Reduction with aluminium and silica / Low
Reduction with carbon and silica / Moderate
Carbothermic reduction / Full
Aluminothermic reduction / Full

Imaging radar has become a keen research topic in recent years. UWB technology provides many advantages to imaging radar such as fine resolution and high power efficiency. The performance of a UWB imaging radar can be further improved by applying polarimetric diversity. The polarimetric signature of objects can be used to enhance the quality of target recognition. Like any other wireless systems, antennas are key factors of radar systems. The focus of this thesis is to develop a dual polarized antenna for UWB imaging radar. An antenna element was designed for the Ku-band and an impedance bandwidth from 8 GHz to 24 GHz was achieved. An orthogonal coax-to-coplanar transition has been developed during this project and this transition is used to feed the antenna element. The antenna elements are successfully applied in two different array configurations. It is demonstrated that these sub-arrays have over 100% fractional bandwidth, good impedance matching, linear phase (almost constant group delay) and uni-directional pattern. These aspects collectively account for the novelty in design. In future, these sub-arrays will be implemented inside a complete array structure of UWB imaging radar.

The metal zirconium (Zr) and its related alloys have high melting points and an excellent resistance to corrosion. Consequently, zirconium is applied in chemical technology and particularly in nuclear reactors. The low neutron-capture cross-section of zirconium, combined with its corrosive resistance, make the metal pre-eminently suitable as cladding for nuclear fuel rods. In nature, zirconium is nearly always found in combination with hafnium (Hf). Chemically the metals zirconium and hafnium strongly resemble each other. However, contrary to zirconium, hafnium has a high neutron-capture cross-section. As a low absorption coefficient for neutrons is essential for fuel rod cladding, the hafnium content of nuclear-grade zirconium should be as low as possible.
Currently, most of the world’s zirconium is produced by the Kroll method. This process is over sixty years old, and due to its inefficient batch production the production costs are high. A (semi-)continuous molten salt electro-refining process could result in a cheaper, purer product that still meets the high requirements of the industry. A new process for the production of pure zirconium has been recently developed and patented at Delft University of Technology. In the current work, fundamental operating aspects of the patented process have been investigated.
The patented process consists of three steps. The first step is the reduction of ZrO2 and HfO2 to Zr and Hf metal. For this step, the solubility of ZrO2 in molten salt has been investigated. Different salt compositions, additives and temperatures have been used. The best results were found using an equimolar NaCl-CaCl2 mixture with 5 mol% CaO and 5 mol% NaF added, at a temperature of 750 °C. This resulted in a ZrO2 solubility of 2.86%.
The second step is the separation of hafnium from zirconium. By contacting a molten Cu-Sn-Zr-Hf alloy with a CuCl2-containing salt, the hafnium is transported to the salt phase. The effects of different salt compositions at different stoichiometric ratios have been investigated. The best results were obtained with a NaCl-CaCl2-CuCl2 salt mixture at a stoichiometric ratio of 1.5, reaching single-step removal efficiencies of 95%. Higher CuCl2 concentrations in the molten salt have a positive effect on the removal efficiency.
The final step is the electro-refining of zirconium from the Cu-Sn-Zr alloy, which has been tested on a laboratory scale. The best results were obtained using vitreous carbon anode lead, a zirconium block cathode and a molten salt electrolyte consisting of equimolar NaCl-KCl with CuCl2. It is essential that the molten salt electrolyte is purified with hydrochloric gas to remove oxide and hydroxide ions. A dense metallic deposit was formed, which consisted of ~25 wt% Cu, ~28 wt% Zr and ~ 47 wt% Sn. The applied potential was too high for selective refining of zirconium. Future experiments should use a lower potential, and have a sufficiently high concentration of zirconium in the molten alloy in order to prevent the deposition of tin and copper.

After fifteen years of service, blast furnace #7 at IJmuiden’s Tata Steel operation was blown down on the 31st of August in 2006 for a small repair. The blow down and salamander tap were successfully completed and afterwards the furnace was quenched with water. All remaining liquids are solidified followed by excavation of the remaining skull. Copper was added to the last ore dump to distinguish the liquids prior to the quench.
Around 300 holes were drilled in the skull, used for explosives. The cores were gathered and used for analysis. Several cores have been analyzed with X-ray fluorescence spectrometry; these rough data were the base of this study.
Carbon lamellas were observed in certain areas of the skull. Their formation appears during slowly cooling of flowing hot metal. These lamellas confirm that part of the skull was solid previous to the blow down of blast furnace #7.
Radial variation of silicon is not detected. Results do show a distinct boundary, which separates material with different concentrations of copper. This is possibly a result of early solidification of the skull.
Confidential report
Full version of the thesis can be requested at TATA Steel IJMUIDEN
At the RD&T department
reference source number: 153291

The basis for this research project was that copper is lost in the Leaching Plant of the Nyrstar Budel zinc smelter. In the section of the Leaching Plant copper is lost, iron and aluminium are precipitated. Sampling of this process showed that the removal of copper from the solution is a function of pH and is mainly linked to the removal of aluminium. Tests with process fluids at stable pH levels showed that ferric ion and aluminium are mainly removed as jarosites at pH = 2 and pH =2,5. Copper is also removed at those pH values and is thus precipitated in jarosite form. This is the actual loss of copper. At pH = 3 and 3,5 more aluminium was removed, but now also in the form of aluminium hydroxides. It was found that copper is adsorbed onto these hydroxides and hence more copper is removed from the solution. At these pH values also jarosites are formed which permanently remove copper, but it is assumed that the adsorption onto aluminium hydroxides prevails. The result of the adsorption of copper onto these hydroxides is that it eventually returns to the FeP in which it has another chance to get lost to jarosites. Hence the only way to prevent copper from being lost is to prevent copper from reaching the FeP. One way to prevent copper from reaching the FeP is not using calcine to neutralise the acid from the SiHALO, but with alternative neutralising agents which do not contain copper. Another way is to prevent copper from leaving the SiHAL. Copper cementation is a method which can totally remove the copper dissolved in the SiHALO. Copper cementation with iron was found to yield the highest recovery and is thus also the most cost effective.
Key words: Copper incorporation, jarosite, alunite, copper cementation